how to average grib files

[Henrique Barbosa]

Dear All,

I have hundreds of thousands of daily model data in grib format
and I would like to create monthly averages of that. I know I could
do that with a grads script, but it would take too much time.

If I had netCDF files, there are tools like NCO that allows one to
add, subtract, merge, average, etc.. a bunch of .nc files
as long as they share the same variables.

Is there something like that for grib files?

Thks,
Henrique